A system and method for creating gamma correction data for a hardcopy device includes generating a data pattern, the data pattern including data representing color pixels and monochrome pixels, dithering the color pixels of the data pattern, and error diffusing the monochrome pixels of the data pattern such that the dithered color pixels and the error diffused monochrome pixels are each N-bit values, N being greater than one. A test pattern is generated based on the dithered color pixels and the error diffused monochrome pixels. The test pattern is scanned into scanned image data, and a plurality of color gamma correction curves and a monochromatic gamma correction curve are generated from the scanned image data.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for creating gamma correction data for an image processing system, comprising: generating a data pattern, the data pattern including data representing color pixels and monochrome pixels; dithering the color pixels of the data pattern; error diffusing the monochrome pixels of the data pattern, wherein the dithered color pixels and the error diffused monochrome pixels are each N-bit values, N being greater than one; generating a test pattern based on the dithered color pixels and the error diffused monochrome pixels; scanning the test pattern into scanned image data; and generating a plurality of color gamma correction curves and a monochromatic gamma correction curve from the scanned image data.
2. A method according to claim 1 , further comprising: scanning an original image; and applying the generated gamma correction curves to the scanned original image.
3. A method according to claim 2 , further comprising reproducing the scanned original image after applying the generated gamma correction curves to the scanned original image.
4. A method according to claim 1 , wherein the data pattern includes photo color pixels and text color pixels, the photo color pixels and the text color pixels each including YMCK data.
5. A method according to claim 4 , wherein the color gamma correction curves include a gamma correction curve corresponding to each of the Y data, the M data, the C data, and the K data of the photo color pixels, and a gamma correction curve corresponding to each of the Y data, the M data, the C data and the K data of the text color pixels.
6. A method according to claim 1 , wherein the data pattern includes a plurality of patches, each patch having a corresponding identifier and density value, and wherein each patch is a patch of color pixels or monochrome pixels.
7. A method according to claim 6 , wherein each patch has a predetermined size of A×B pixels, where A and B are greater than one.
8. A method according to claim 6 , wherein each patch corresponds to one of Y photo color pixels, M photo color pixels, C photo color pixels, K photo color pixels, Y text color pixels, M text color pixels, C text color pixels, K text color pixels, and monochrome pixels.
9. A method according to claim 8 , wherein the step of dithering includes identifying a dither pattern for each patch of color pixels based on the identifier and the density value of the patch, and wherein the step of error diffusing includes identifying an error diffusion pattern for each patch of monochrome pixels based on the identifier and the density value of the patch.
10. A method according to claim 9 , wherein the test pattern is generated from the identified dither patterns and error diffusion patterns.
11. A method according to claim 1 , wherein the scanning comprises: reading the test pattern with a color CCD; and reading the test pattern with a monochromatic CCD.
12. A method according to claim 11 , wherein the color gamma correction curves are generated from the test pattern read by the color CCD, and wherein the monochromatic gamma correction curve is generated from the test pattern read by the monochromatic CCD.
13. A method according to claim 12 , wherein the test pattern includes photo color pixels and text color pixels, the method further comprising: determining the location of the photo color pixels and the text color pixels based on the data pattern; and generating gamma correction curves for the photo color pixels and gamma correction curves for the text color pixels in accordance with the determined locations of the photo color pixels and the text color pixels, respectively.
14. A method according to claim 1 , where N is 8.
15. An image processing system for creating gamma correction data for a hardcopy device, comprising: an image data generator which generates a data pattern, the data pattern including data representing color pixels and monochrome pixels; an image processor configured to dither the color pixels of the data pattern and to error diffuse the monochrome pixels of the data pattern, wherein the dithered color pixels and the error diffused monochrome pixels are each N-bit values, N being greater than one; a hardcopy device which generates a test pattern based on the dithered color pixels and the error diffused monochrome pixels output from the image processor; a scanner which scans the test pattern into scanned image data; and a gamma correction curve generator configured to generate a plurality of color gamma correction curves and a monochromatic gamma correction curve from the scanned image data output from the scanner.
16. An image processing system according to claim 15 , further comprising: a gamma correction processor which applies the generated gamma correction curves to image data of an original image scanned by the scanner.
17. An image processing system according to claim 16 , wherein the hardcopy device reproduces the scanned original image after the application of the generated gamma correction curves by the gamma correction processor.
18. An image processing system according to claim 15 , wherein the data pattern generated by the image data generator includes photo color pixels and text color pixels, the photo color pixels and the text color pixels each including YMCK data.
19. An image processing system according to claim 18 , wherein the color gamma correction curves include a gamma correction curve corresponding to each of the Y data, the M data, the C data, and the K data of the photo color pixels, and a gamma correction curve corresponding to each of the Y data, the M data, the C data and the K data of the text color pixels.
20. An image processing system according to claim 15 , wherein the data pattern generated by the image data generator includes a plurality of patches, each patch having a corresponding identifier and density value, and wherein each patch is a patch of color pixels or monochrome pixels.
21. An image processing system according to claim 20 , wherein each patch has a predetermined size of A×B pixels, where A and B are greater than one.
22. An image processing system according to claim 20 , wherein each patch corresponds to one of Y photo color pixels, M photo color pixels, C photo color pixels, K photo color pixels, Y text color pixels, M text color pixels, C text color pixels, K text color pixels, and monochrome pixels.
23. An image processing system according to claim 22 , wherein the image processor is further configured to identify a dither pattern for each patch of color pixels based on the identifier and the density value of the data pattern, and to identify an error diffusion pattern for each patch of monochrome pixels based on the identifier and the density value of the data pattern.
24. An image processing system according to claim 23 , wherein the test pattern is generated from the identified dither patterns and error diffusion patterns.
25. An image processing system according to claim 15 , wherein the scanner comprises a color CCD and a monochromatic CCD, wherein the scanning of the test pattern by the scanner includes reading the test pattern with the color CCD and the monochromatic CCD.
26. An image processing system according to claim 25 , wherein the color gamma correction curves are generated from the test pattern read by the color CCD, and wherein the monochromatic gamma correction curve is generated from the test pattern read by the monochromatic CCD.
27. An image processing system according to claim 26 , wherein the test pattern includes photo color pixels and text color pixels, and wherein the gamma correction curve generator is further configured to determine the location of the photo color pixels and the text color pixels based on the data pattern, and to generate gamma correction curves for the photo color pixels and gamma correction curves for the text color pixels in accordance with the determined locations of the photo color pixels and the text color pixels, respectively.
28. An image processing system according to claim 15 , where N is 8.
29. A method for creating gamma correction data for an image processing system, comprising: generating a data pattern, the data pattern including data representing color pixels and monochrome pixels; applying image processing to the color pixels of the data pattern and the monochrome pixels of the data pattern, wherein the image processed color pixels and monochrome pixels are each N-bit values, N being greater than one; generating a test pattern based on the image processed color pixels and monochrome pixels; scanning the test pattern into scanned image data; and generating a plurality of color gamma correction curves and a monochromatic gamma correction curve from the scanned image data.
30. An image processing system for creating gamma correction data for a hardcopy device, comprising: an image data generator which generates a data pattern, the data pattern including data representing color pixels and monochrome pixels; an image processor configured to apply image processing to the color pixels of the data pattern and to the monochrome pixels of the data pattern, wherein the image processed color pixels and the image processed monochrome pixels are each N-bit values, N being greater than one; a hardcopy device which generates a test pattern based on the image processed color pixels and the image processed monochrome pixels output from the image processor; a scanner which scans the test pattern into scanned image data; and a gamma correction curve generator configured to generate a plurality of color gamma correction curves and a monochromatic gamma correction curve from the scanned image data output from the scanner.
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March 6, 2003
August 7, 2007
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